This project aims to develop a diagnostic center for Alzheimer disease (AD) and to ascertain families with a proband with AD to serve as a resource for genetic linkage studies in collaboration with the NIMH. We aim to: 1) develop a diagnostic protocol for the assessment of families with familial Alzheimer's disease. 2) determine the appropriate small family configurations for future linkage studies. 3) collect 133 families, ascertained through a proband with Alzheimer's disease with one or more sibs who have been examined and classified as probable Alzheimer's disease by NINCDS-ADRBA criteria. 4) develop a protocol for the collection of blood samples from these families to allow the establishment of permanent lymphoblastoid cell lines.